SLEEP eight hours a day is good for health. But investigators doubted it as a habit that arose in the 20th century. Researchers said the habit of sleep in the previous centuries is different.
Experts from the American University of Virginia said that the need to sleep for eight hours is a common misconception. But the mistakes brought a huge impact on modern society. A lot of people feel relax after sleep less than eight hours, especially for those who often wake up during the night.
However, the researcher Roger Ekirch prove that wake up in the middle of the night is also helpful. Since a long time ago, human did biphasic sleep. Each sleep period, lasted for four hours. During the pause time, typically used to pray, to dream with open eyes, talking with his wife, and even visit others.
Most people sleep early and spend nine to ten hours in bed. Robert Ekirch has collected 500 historical documents from different ages, concerned with sleep biphasic. The document came from African tribes, the people of Ancient Greece, and the monks of the middle ages, who could sleep and rest within four hours. Uniquely, none of them complained of insomnia.
According to Ekirch, the rhythm of life has changed since the widespread distribution of electrical lamps and lanterns in the 19th century until the 20th century. After that time, a lot of people complain lack of sleep. Since then many researchers claim that humans need to sleep more.
However, some people still wake up at night. For some people wake up at night is a problem. In the 1990s, a scientists from Germany, Thomas Wehr, conducting research involving dozens of volunteer to spend 14 hours a day in the dark. After that, he try to research switch from a long sleep for eight hours into two phases that is four hours.
What is the benefits of biphasic sleep? Scientists said that in addition to having a better sleep, a person will also could recall his dream, which could provide an opportunity for us to tap into our subconscious. However, scientists are not sure modern humans can get back rest and sleep for four hours. So, sleep for eight hours is believed to be the human needs, whereas for the first time is just a habit.